Structural Test Design and Interpretation for Aerospace (STDI)

This three-day course provides a rigorous look at structural testing and its roles in product development and verification for aerospace programs. The course starts with a broad view of structural verification throughout product development and the role of testing. The course then covers planning, designing, performing, interpreting, and documenting a test. 

The course emphasizes static loads testing and vibration testing on a shaker, including notching and force limiting.  Modal survey testing, centrifuge testing, and acoustic testing are touched on as well. Several case studies are presented after first tasking the class with brainstorming how they would design effective tests.

The one-day computer workshop, Notching and Force Limiting Workshop (NFLW), offered the day after STDI completion, is an optional supplement to the STDI course.  The tuition for all four days of training is $2,800.

All engineers and managers involved in ensuring that flight vehicles and their payloads can withstand mission environments. 

• Identify and clearly state test objectives
• Design (or recognize) a test that satisfies the identified objectives while minimizing risk
• Establish pass/fail criteria
• Design the instrumentation
• Interpret test data
• Write a good test plan and a good test report

1. Overview of Structural Testing. Reasons for doing a structural test? Structural requirements; the building-blocks verification process; verification logic flows; qualification, acceptance, and protoflight testing; selecting the right type of test; pass/fail and success criteria; test management: documents, reviews, and controls
2. Designing and Documenting a Test. Designing a test, suggested contents of a test plan, test-article configuration, boundary conditions, ensuring adequacy of a strength test, a key difference between a qualification test and a proof test, success criteria and effective instrumentation, preparing to interpret test data, documenting with a test report
3. Loads Testing of Small Specimens. Applications and objectives, common loading systems, test standards, case history: designing a test to substantiate new NASA-STD-5020 criteria for analysis of preloaded bolts
4. Static Loads Testing of Large Assemblies. Introduction to static loads testing, Test factors per DOD and NASA standards. Special considerations, introducing and controlling loads, developing the load cases, example: developing load cases for a truss structure, be sure to design the right test!, centrifuge testing
5. Testing on an ElectrodynamicShaker. Test configuration, limitations of testing on a shaker, fixture design, deriving loads from measured accelerations, Sine sweep testing.  Deriving damping from test data. Sine burst testing, Understanding random vibration, random vibration testing, interpreting test data.
6. Notching and Force Limiting. Understanding notching and its technical justification, case history of notching without technical rationale, methods of notching, the impedance effect, NASA’s semi-empirical method, examples, modification during test, response limiting, manual notching.
7. Modal Survey Testing and Math.  Model. Correlation Test objectives and target modes, designing a modal survey test, key considerations, test configuration and approaches, checking the test data, correlating the math model
8. Case History: Vibration Testing of a Spacecraft Telescope. Case History: Vibration Testing of a Spacecraft Telescope Overview, initial structural test plan, problem statement, revised test plan, testing at the telescope assembly level, testing at the vehicle level, lessons learned and conclusions
9. Summary

Tom Sarafin is President and Chief Engineer of Instar Engineering and Consulting, Inc. He has worked full time in the space industry since 1979 as a structural engineer, a mechanical systems engineer, a project manager, and a consultant.  Since founding Instar in 1993, he’s consulted for NASA, DARPA, the DOD Space Test Program, Lockheed Martin, DigitalGlobe (Maxar), Sierra Nevada Corp, Spaceflight Industries, Millennium Space Systems (Boeing), and other organizations.  He was a key member of the team that developed NASA-STD-5020, “Requirements for Threaded Fastening Systems in Spaceflight Hardware” (March 2012).  He is the editor and principal author of Spacecraft Structures and Mechanisms:  From Concept to Launch and is a contributing author to Space Mission Analysis and Design.  He’s also the principal author of a series of papers titled “Vibration Testing of Small Satellites.”  Since 1995, he has taught over 300 courses to more than 6000 engineers and managers in the aerospace industry.